The present invention relates to a heat sink, and in particular to a heat sink which may be used for cooling integrated circuits, laser devices, electric or other electronic devices.
Heat sinks are known to comprise a plate, generally made of aluminum and provided on the top with cooling fins or pins, which directly contacts the housing containing the integrated circuits, in order to increase the heat exchange between the housing and the outside environment, and thus reducing the temperature of the circuit junctions. Since in the last years the size and the power of the integrated circuits are increased in geometric progression, these known heat sinks are no longer capable of dissipating the heat generated by the new circuits. Therefore, new heat sinks have been designed comprising an axial cooling fan arranged above the fins in order to increase the heat exchange between the heat sink and the surrounding air.
In order to reduce the size of the heat sink and optimize its thermal efficiency, such a cooling fan is arranged straight above the cooling fins, wherefore the air flow generated by the fan perpendicularly hits the conductive plate, resulting in turbulence and pressure drops which greatly reduce the heat exchange and thus the heat sink efficiency. Furthermore, the central portion of these known heat sinks is more heated, but the air flow coming from the fan is here reduced. In fact, for space requirements, the fan motor is inserted into the hub of the bladed rotor generating the air flow, so that it tends to outwardly flow without affecting the column of air between the rotor hub and the plate.
In order to overcome such drawbacks, a fan could be used with a larger rotor and a more powerful motor, but this solution would result in a more bulky and noisy heat sink, with evident problems when used inside an electronic device.